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[219.74.209.211]) by smtp.gmail.com with ESMTPSA id z9-20020aa791c9000000b00640dbbd7830sm6044479pfa.18.2023.07.30.04.50.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 30 Jul 2023 04:50:12 -0700 (PDT) From: Leon Hwang To: ast@kernel.org Cc: daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, hawk@kernel.org, rostedt@goodmis.org, mhiramat@kernel.org, mykolal@fb.com, shuah@kernel.org, hffilwlqm@gmail.com, tangyeechou@gmail.com, kernel-patches-bot@fb.com, bpf@vger.kernel.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Subject: [PATCH bpf-next v4 1/2] bpf, xdp: Add tracepoint to xdp attaching failure Date: Sun, 30 Jul 2023 19:49:50 +0800 Message-ID: <20230730114951.74067-2-hffilwlqm@gmail.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230730114951.74067-1-hffilwlqm@gmail.com> References: <20230730114951.74067-1-hffilwlqm@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org When error happens in dev_xdp_attach(), it should have a way to tell users the error message like the netlink approach. To avoid breaking uapi, adding a tracepoint in bpf_xdp_link_attach() is an appropriate way to notify users the error message. Hence, bpf libraries are able to retrieve the error message by this tracepoint, and then report the error message to users. Signed-off-by: Leon Hwang --- include/trace/events/xdp.h | 17 +++++++++++++++++ net/core/dev.c | 5 ++++- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h index c40fc97f94171..cd89f1d5ce7b8 100644 --- a/include/trace/events/xdp.h +++ b/include/trace/events/xdp.h @@ -404,6 +404,23 @@ TRACE_EVENT(mem_return_failed, ) ); +TRACE_EVENT(bpf_xdp_link_attach_failed, + + TP_PROTO(const char *msg), + + TP_ARGS(msg), + + TP_STRUCT__entry( + __string(msg, msg) + ), + + TP_fast_assign( + __assign_str(msg, msg); + ), + + TP_printk("errmsg=%s", __get_str(msg)) +); + #endif /* _TRACE_XDP_H */ #include diff --git a/net/core/dev.c b/net/core/dev.c index 8e7d0cb540cdb..49bed890f807e 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -133,6 +133,7 @@ #include #include #include +#include #include #include #include @@ -9472,6 +9473,7 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) struct bpf_link_primer link_primer; struct bpf_xdp_link *link; struct net_device *dev; + struct netlink_ext_ack extack; int err, fd; rtnl_lock(); @@ -9497,12 +9499,13 @@ int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog) goto unlock; } - err = dev_xdp_attach_link(dev, NULL, link); + err = dev_xdp_attach_link(dev, &extack, link); rtnl_unlock(); if (err) { link->dev = NULL; bpf_link_cleanup(&link_primer); + trace_bpf_xdp_link_attach_failed(extack._msg); goto out_put_dev; }